Performance Comparison of Physical Server and Virtual Machines

Single Hex Core

With a single hex core CPU, Genesys recommends 200 ports as a reasonable peak port capacity on a physical server with a single X5670, assuming that all criteria have been met. 300 ports can be achieved with a three-VMs configuration of the same hardware, with a single X5675 (performance is slightly better than X5670). The graph below compares overall CPU usage:

Figure 1: Comparison of System Usage between Physical Server and VM from Single Hex Core

Memory usage for MCP scales linearly against port capacity:

Figure 2: Comparison of MCP Memory Usage between Physical Server and VM from Single Hex Core

Figure 3: Comparison of Max Jitter between Physical Server and VM from Single Hex Core

Figure 4: Comparison of Max Delta between Physical Server and VM from Single Hex Core

A strong correlation exists between Max Jitter Buffer and Max Delta, regarding audio quality. A physical server can meet all criteria when its port capacity is 200 or below. Port capacity that is between 200 and 220 may impact audio quality, since both Max Jitter buffer and Max Delta are just slightly beyond the passing criteria. You can consider 220 as peak performance, if audio quality is not strictly required and can be waived. However, when port capacity reaches 230 or beyond, the two values become so big that there is apparent audio quality impact.

Table 1: Disk IOPS of system level from a physical server with a single hex core

Ports

Disk IOPS Physical Server

Total

Reads

Writes

60

11.13

0.001

11.13

120

21.82

0.001

21.82

180

32.03

0.001

32.03

200

34.95

0.001

34.95

210

36.53

0.001

36.53

220

37.76

0.001

37.76

230

39.48

0.001

39.48

240

43.33

0.002

43.33

Table 2: Disk IOPS of sum of all VMs of single hex core

Ports

Disk IOPS VMs Overall

Total

Reads

Writes

120

20.68

0.101

20.58

240

36.29

0.070

36.22

270

41.39

0.087

41.30

300

45.57

0.065

45.50

330

48.85

0.000

48.85

360

51.69

0.000

51.69

390

57.82

0.002

57.82

Disk IOPS in Disk IOPS of sum of all VMs of single hex core table is the sum of Disk IOPS from all VMs. Also, IOPS is measured from each VM and then totaled, to determine overall IOPS. The same method is applied to all Disk IO calculations for VM environments in this series of tests.

Also in the above two tables, the IOPS Reads value is quite small because most of the operations are Writes.

The graph below compares the two IOPS tables above:

Figure 5: Comparison of System Disk IOPS Physical Server and VM from Single Hex Core

System level disk IOPS is scaling linearly against port capacity for both physical server and virtual machines.

SSD is only used on VM env as cache folder of MCP recording while SAS HDD drive is used to installed OS and MCP.

Dual Hex Cores

With a host of dual hex core CPUs (2x X5675@3.06GHz) with 32 GB RAM, we also compare the results from physical server and VM env. In VM env, on same hardware spec, 3 VMs are configured with 4 vCPU and 8 GB RAM assigned to each VM. Only one MCP installed on each VM and a SSD partition is used as cache folder for MCP recording.

The graph below depicts the overall system CPU usage:

Figure 6: Comparison of System Usage between Physical Server and VM from Dual Hex Cores

The next two graphs show 95 percentile values of Max Jitter and Max Delta from sample RTP stream quality analysis: